Sulfolanyl esters



Manes. 12, 194s I clopentane-l,1-dioxide,

PATENT orslcsf BULFOLANYL ss'rans -Ru'pert C. .Morrll, Berkeley, and Edward C.

, Shokal, Oakland. 'Calif.,asslgnors to Shell De- I velopl'nent Company, San Francisco, Calif., a

corporation of Delaware No Drawing. Application August 1, 1945,

- Serial No. 808.375

This invention relates to a'novel and: particularly useful class of compounds comprising the cyclic sulfones having at least oneof the nuclear 3 Claims. (cacao-s29) carbon atoms directly attached to the acyloxy I radical of a higher saturated monocarboxylic acid. -More particularly, the invention pertainsv to suliolanyl and sulfolenyl esters of the higher saturated monocarboxylic acids having at least six carbon atoms.

' The term "sulfolane" refers to a compound having a saturated cyclic structure containing four carbon atoms and a sulfur atom in a ring, the

sulfur atom of this five-membered heterocyclic ring having two oxysen atoms attached thereto.

The structural formula of sulfolane is:

H:CCH:

B: l Bl 0 o This compound has also' been called "thiacy- "thiolane- 1,1-dioxide,"

cyclotetra'methylene suli'one or fdihydrobutadiene sulfone. As employed herein, the term a -sulfolanyl radical is the radical resulting from the removal of one or more hydrogen atoms from v the nuclear carbon'atoms in sulfolane, and compounds containing such a radical, including sulfolane itself, are generically, referred to herein as ,sulfolanyl compounds."

.The term sulfolene," as employed herein, refers to an unsaturated compound containing four carbon atoms and a sulfur atom in a ring, said structure having a single olefinic linkage between two adjoining carbon atoms, with the sulfur atom having two oxygen atoms attached thereto, and with the remaining free bonds of the nuclear carbon atoms in the ring being attached to hydrogen atoms. This compound has is termed B-sulfolene. The term a sulfolenyl radical" is the radical resulting from the removal of one or more hydrogen atoms from the nuclear carbon atoms in sulfolene, the radical being me- 'fixed' by either 2- or 3- when referring to par- ,tlcular compounds. Compounds containing such a radical, including 2- or 3-sulfolene itself, aregenerically referred to herein as "sulfolenyl compounds.

In accordance with well-recognized nomenclature practice, the terms sulfolane and either 2- or 3-sulfolene may also form part of the name of various substituted compounds,asb-sulfolanol; sulfolan-2,4-dicl, z-sulfolen-i-ol and 2-sulfolen- 4,5-diol, such compounds being formed by substituting for one or more of the hydrogen atoms attached to the carbon-sulfur. nucleus a corresonding number of other functional groups in the numbered position of the ring indicated in the case of each particular compound.

The term acyloxy radical of a higher saturated monocarboxylic' acid refers to a radical having the general formula wherein R1 is a saturated organic radical, preferably a saturated hydrocarbon radical containing at least five carbon atoms.

An object of the invention is to provide a novel class of compounds possessing unexpected and useful properties. Further objects willbe apparent from the following description of the invention.

Esters of the type of B-sulfolanyl acetate are disclosed in the prior art. In all of these compounds the radical which is attached by means 7 of the carbonyl (-COO) linkage to the sulfolanyl or sulfolenyl radical is'the methyl radical which contains just one carbon atom. Compounds have now been prepared wherein the radical joined tcthe cyclic sulfone group by means of thecarboxyl radical is a saturated hy- V drocarbon radical .of at least five carbon atoms. .In other words, the newly prepared compounds comprise a sulfolanyl or sulfolenyl radical linked 'to at least one saturated acyloxy radical of at least six carbon atoms. Surprisingly, it has been found that thesehlgher saturated esters of the invention possess properties which are markedly superior to those of the esters of the lower acids, e. g. sulfolanyl acetate. A sulfolanyl acetate is a water-soluble compound. which is quite unstable and therefore not suited for many purposes. For

example, sulfolanyl acetate is not of value as a 'piasticizer because of its instability. However,

esters of the higher saturated monocarboxylic acids such as suliolanyl caproate and suli'olanyl naphthenate are particularly valuable as plasti= cizers, e. g. for cellulose acetate and vinyl chloride polymers. Morever, these 'sulioianyl and sulfoienyl higher esters possess qualities markedly superior to those of the corresponding esters of the unsaturated acids, particularly as plasticizers for use in the preparation of clear, water-white resins and the like. For the sulfoianyl esters of the unsaturated acids, e. g. sulfolanyl oleate, are unstable and readily undergo further reaction e. g. oxidation on standing, and turn yellow, whil the higher saturated monocarboxyiic acid esters are stable and do not change color upon standing. These properties could not be foreseen, and they are of such a nature as to. make the compounds the invention particularly useful in many applications.

- The novel compounds of the invention comprise the substituted or unsubstituted sulfolanyl and sulfolenyl derivatives wherein at least one nuclear carbon atom is directly attached to an acyloxy radical of a higher saturated monocarboxylic acid. The novel suliolanyl higher esters, i.- e. compounds in which at least one of the nuclear carbon atoms radical containing at least flve carbon atoms which is preferably an alkyl radical, and the it's are members of the group consisting of the hydrogen atom and the saturated aliphatic hydrocompounds of the invention may be prepared by" an csteriflcation reaction between the carboxylic' of a suliolane ring is directly attached to the acyloxy radical of a higher saturated monocarboxylic acid of'at least six carbon atoms, may be represented by the general structural formula:

-sulfolan-2,3-diol,

carbon radicals. ,For example, when R1 is the n-amyl radical and each R is ,a hydrogen atom,

the above formula represents S-suliolanyl capro ate,'that is the caproic acid ester of B-suliolanol. Another group of suitable compounds consists of the esters of the 3,4-suliolandiols' and 3,4-sul-- folendiols in which both ring-attached hydroxy carboxyiic acids, e. g. sulfolandiol-3-caproatei-naphthenate, and the like. p

The higher saturated monocarboxylic acid ester acid and acyclic sulione containing at least one hydroxyl radical-directly attached to one of the nuclear carbon atoms. Suitable hydroxylated cyclic sulfones which may thus be esterified are 3-sulfolanol, 2-sulfolen-4-ol, sulfolah-3,4-dipi,

su1foian-2,4-'dioi, 2-sulfolen- 5-01, 2-suliolen- 4,5-diol, andthe various hydrocarbon-substituted hydroxylated sulfola'nyi and sulfolenyl compounds such as 3-methyl-3-suli0- lanol, 2-ethyl -3-sulfolan'ol, 3-methyl-2-sulfolanol, 2-methyi-3-ethyl-3-sulfolanol, z-methylsulfolan-ZiA-dibl, 2,4-dimethyl-3 sulfolanol, and the like and their homologues and analogues. The higher-saturated monocarboxylic acids which maybe employed as'one of the two reactants in the production of the novelsaturated esters are characterized by, possessing a carboxyl group linked to a saturated hydrocarbon of atleast five carbon atoms. The saturated monocarboxylic acids which may be employed singly or in mixtures include: k capryli c acid, pelargonic'acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nondecylic acid, arachidic acid, the naphthenicacids, cyclopentane monocarboxylic acid, 3,3,4-trimethylcyclopentane=-l-acetic acid, isocampholic acid, cyclohexane monocar boxyiic acid, eicosane-carboxylio acid-(1), be-

' henic acid, lignoceric acid, cerotic acid, melissic HzScOv, HIPOs, HCI, HBr, H4Pa01, HClOa, HC1O4,

. A preferred subgroup of the novel compounds comprises the sulfolanyl and sulfolenyl compounds in which a single saturated acyloxy radical of at least six carbon atoms is directly attached to the ring carbon atom in the 3-position, the'remaining free bonds of the nuclear carbon atoms being taken up by hydrogen atoms and/or wherein R1 designates a saturated hydrocarbon acid, psyllastearic acid, and the-like and their homologues, analogues and suitable substitution products.

The esteriflcation reaction may be executed in the presence or absence of a catalyst. Suit- ,able promoters or catalysts which may be used HNOa. and the like. Mineral acid substances or the type 01 SO2Clz,' SOCla, SOBra. N02, N203,

NOCl, PCla, PCls, and the like may also be employed. Inorganic acid-acting salts such as 'ZnSOa ZilCln. ZnBra, FeCla, A1013, C0012, NlCh,

FeflSOOa. AI:(SO4) 3, NaHSOo, NaHzPO4, and the,

' anynumber-oi ways. ,One method of esteriflcation comprises heating the saturated monocar-- boxylic acid of six or more carbon atoms in consulfolandiol-3,4-dinaphthcnate,

caproic acid, heptoic acid,

. s tact with the hydroxylated cyclic sulfone. preferablyin a suitable reaction vessel equipped with means for agitating the reactants. The reactants may be introduced into the reactor separate-- ly, or they may be mixed prior to their introduction thereinto. In many cases it is desirable to en'ect the esteriiicatlon by heating the reactants at about the boiling temperature of the reaction mixture at approximately atmospheric pressure. However, in some instances, the use ,of super-atmospheric pressures and higher temperatures substantially as soon as they are formed. In some instances,'this removal may be effected byallowing-the process to take place at a temperature suillciently high to permit distillation of the ester and/or water from the reaction mixture. Thus,

' it is possible to operate with a distilling or fractionating apparatus which is in direct communication with the reaction vessel in such a manner that vapors from the latter are introduced at a suitable point in the separating column. In most cases the distilling apparatus is .operated under heavy reflux with concurrent distillation of azeotropic mixtures comprising the ester, water and other constituents of the reaction mixture from the reaction vessel. In some instances it may be desirable to aid the removal of the ester and/or water by effecting the reaction in the presence of an inertv substance which may or may not form low-boiling azeotropic mixtures with the reaction products under the operating condi-.

tions. Certain. hydrocarbons, and particularly aromatic hydrocarbons, e. g. benzene, are among the suitable inert substances which may be employed for this purpose.

The vapors removed from the reaction vessel may be condensed and the novel esters of the hydroxylated sulfolanyl and/or sulfolenyl compounds may be recovered therefrom by any suitable means such as stratification, fractionation, extraction, salting out. use of drying agents, and

the like, the particular recovery system to be employed being dependent upon the physical and especially upon the azeotropic properties of the condensate and its constituents.

The novel esters may be prepared by reacting a single monohydroxy orpolyhydroxy sulfolanyl or sulfolenyl compound with a single saturated monocarboxylic acid of at least six carbon atoms. Mixed esters may be prepared by reacting a polyhydroxylated cyclic sulfone with a mixture of different saturated monocarboxylic acids each of which contains at least six carbon atoms. Also included in the scope of the invention are those mixed esters formed by reacting a polyhydroxylated sulfolanyl or sulfolenyl compound with a mixture of a higher saturated monocarboxylic acid with one or more different carboxylic acids, e. g. sulfolanediol-3-caproate-4-acetate.

The following examples serve to illustrate the invention.

Example I 3-suliolanyl caproate was prepared by warming until homogeneous a mixture of about 642 parts by weight of 3-suliolanol and about 480 parts by weight oi technical caproic acid with approximately 38 parts by weight-oi per cent sul- ,furic acid. adding approximately 500 cc. of ben- 'zene and refluxing with a kettle temperature in theneighborhoo'd of C. Water wasremoved by means of a separating stillhead. the reaction mixture'was washed and distilled. The 3-sulfolanylcaproate recovered has a boiling point of 127 C. to 130 C. at 0.5 mm. and melts at 39 C. to 40 C.

' Example II ii-sulfolanyl stearate is prepared by reacting 3- 'suliolanol with stearic acid according to the prov cedure described in Example I.

' Example 111 A mixture of about 293 grams of B-sulfolanol, 500 grams of naphthenic acids of an average was refluxed for several hours. Water was removed azeotropically, and the reaction mixture washed and distilled. There was obtained about 558.5 grams of 3-suliolany1 naphthenate'which had a boiling point of C. to 176 C. at about 1 mm. I

Example IV 2-sulfolen-4 olis reacted with caproic acid according to the process described in Example 111 to obtain a good yield of 4-(2-sulfolenyl) caproate.

The novel sulfolanyl and sulfolenyl esters of the higher saturated monocarboxylic acids may also be formed by a variety of other suitable current formation of the desired 3-sulfolanyl caproate and of the alkanol, Le. methanol. This "process may also be employed to produce the unsaturated sulfolenyl esters, for example, by an ester-exchange between methyl caproate and 3- sulfolenol.

By following the procedures described .above rate, sulfolandiol-3,4-distearate, sulfolandiol-2-' caproate-3-naphthenate, and the like and their homologues and analogues.

The novel products of the present invention find utility in a large variety of industries. The compounds are suitable as intermediates for the manufacture of other products which are also highly useful. The novel compounds are particularly useful in the natural and synthetic resin and lacquer industries, and they may be used as insecticides, parasiticides and fungicides or as ingredients of insecticidal, parasiticidal and fungicidal compositions. When the higher saturated esters oithe cyclic sulfones are further reacted, e. g. sulfated, they may serve as detergents. The

compounds also find utility in the preparation of printing inks and anti-corroding paints.

We claim as our invention:

' 1. S-auliolanyl caproate having the structui'e o g E 011405,). -o-'o--om 2. S-auifolcnyi na wherein represents the ccylosxy radical of ncphthen'ic acid.

3. A suiiolanyl ester having the struct zre 0 Eli-0,-

' Q ro/ \o phthenaba having the strucf J 8 I wherein at least one of the Rs is an acyloxy radical 01 the structure v in each of the other R's is a member selected from the group consisting of the hydrogen atom and m the saturated aliphatic hydrocarbon radicals.

RUPERT C. MQRRIB.

v W C.

mews an M The foilcwing references are of record in this I file of this patent: v

UNI STATES PATENTB Number Name 1 Date 2,219,006 D8118 00$. 22, l fi 2,372,180 MOM-'18 at 8,1 MM. 20, 1945 2,393,925 1 Morris 6% B1. Jan. 29, 13

OTHER REFERENCES 7 Backer: Recueil des Travaux des Chimique des Pays Bas, vol. 53, page 527 (1934); 

